Libbie Henrietta Hyman (1888-1969): from developmental mechanics to the evolution of animal body plans

Libbie Hyman is the most influential comparative invertebrate zoologist of the 20th century in the English-speaking world. During the first part of her career Hyman conducted experimental research on the metabolic and developmental physiology of a host of invertebrates and vertebrate embryos. One important aim of these studies was to elucidate the hidden processes of morphogenesis. Some of the papers from this early phase of Hyman's career already contain the seeds for her subsequent occupation with comparative embryology and morphology to address questions about animal body plan evolution and metazoan phylogeny. Hyman's views on invertebrate evolution and phylogeny have become widely incorporated into textbooks, and until very recently Hyman's ideas have been equated with 'traditional' or 'classical' views on animal evolution. Hyman's enduring fame and significance for modern evo-devo is primarily based upon her magisterial six-volume series The Invertebrates, which is the most encompassing single-author synthesis of invertebrate structure and development of the 20th century. In The Invertebrates Hyman addressed numerous questions about the evolution of animal body plans and metazoan phylogeny that are nowadays core items on the research agenda of evo-devo. In addition, Hyman had a lasting influence on teaching with the publication of her widely used laboratory manuals for elementary zoology, and especially comparative vertebrate anatomy.